Explosionproof fuse



1,619,640 W. W. SLOANE EXPLOSIONPROOF FUSE Filed June 24. 1920 2Sheets-Sheet 'L /v V z 57 i March l 1927.

W. W. SLOANE EXPLOSIONPROOF FUSE Filed June 24, 1920 March 1 1927.

2*-Sheets-/Sheet 2 n i Ewan/of? JZOa/ze, (Jfyf @mu/@ my Patented Mar. 1,1927.-

unirse stares A'EENT QFFEQE.

XVILLIAIiIvV/. SLOANE, OF CHICAGO, ELLNCS, ALSSGNCR TO GOGDMANMANUFACTUR- ING COMQANY, GF ClrCAsrO,l ILLNCvI-S, A CORPORATION OFILLINOIS;

EXPLOSON? Application filed'iunc 24,

This invention relates to improvements in cxplosioi'i-prootl electrical.tuses or cutouts, and has for its principal object to provid-e a satetyfuse for use in gaseous mines, or under similar conditions inA whichexplosions maybe caused by the arcing o' exposed fuse connect-ions. Y

To` this end, I provide an improved construction con'iprisino arenevzble Vtuse element and a casing therefor, in which the fuseisenclosed in the casing` and-cannot be removed therefrom Without firstbreaking the electric circuit.

A further object of this invention is to provide a construction in whichit is practically impossible to insert a substitute l'or the fuseelement between the fuse connections.

Further objects Will appear from the following description, referencebeing' had to the accompanying' drawings, in which Figure l is a'vertical cross-section ot my improved. device,` showing' the fuseelement in locked position in the. casing.

Figure 2 is an end vienT ot the casing.

Figure 3 is a vertical cross-section ot" the casingl and fuse elementtaken on line 3 3 oi Figure l.

Figure el is a vertical cross-section olf' the fuse element, removedfrom the casing.

Figure 5 is a detail.

Referring nouv to the details ot the construction, my device comprisestwo main elements, namely; an outer casing l, and a removable fuseelement 2 adapted to be inserted at one end of the casinan l, and lockedtherein, so as to provide a practicallyY airtight enclosure.

T he outer casing l comprises a cylindrical body 3, preferably ot metal,enclosed at one end by a thr aded plug Ll and at the opposite end by thet'use element 2 already re- 'lerred to. A pair ot metallic connecting,`members 9'and l() are separatel from each other in the casing, andencircle the chamber adjacent the outer Wall 3 of the casing, but areinsulated therefrom by means or suitable insulation pieces l1 andl2,.respective ly. Connecting. members 9 and l0 each comprise aspringmember 9a, and a contiguous conductingmember, or shunt 9b. Thespringmember 9e is preferably of phosphor bronze, or other materialsuitable tor use as a spring, While the conducting member, or shunt7 9",is preferably made up ot a ROOF FUSE.

1929. Serial No. 391,393.

pliu'alityoi thin copper plates, oit high rela tive conductivity`r so asto carry most of the current. This arrangement is provided so that thetensional properties ot the spring member 9a are not atliected byheating'.V ffs shown in Figure 3, the connecting' members 9 and 19' arepreferably constructer in the form of rings, and arranged eccentril:lwith respect to the casing rl`hey are connected to the outside terminals5 and G bv means ot studs 7 and 8, having heads i3 and lei'. The4 studsare inserted thru suitable holes in the rings 9 and l0. and secure thesaid connecting' rings by threaded nuts l5 and NS on the terminals.Contact shoes i7 and i9 arenttaclied'to the upper portions otA the rings9 and l0 respectively, andare adapted to provide contact Withcorresponding' contact members 19 and 29 carried by the fuse ele- .ment2.

Inside ot the ring-shaped connectors 9 and 19 is inserted an insulating`member 2l which extends practically the. entire length ot the casing,and is held in place by insu* lating,l dii-lts 23, 241 and'25 supportedby the casing- Wall 3. Said insulating member (shown in detail in nigure5)' is so proportioned in cross-section as to receive the fuse element 2therein, and includes a depending wall portion 26 extending the fulllength thereof. which receives the contact members 19 and'20 ot saidtusefelemcnt Whenvthe Jfuse element is inserted in its invertedposition, as willihcreinatter be more fully describedz Referring nowparticularly to the tuse ele mentY 2, l prefer to utilize a so-called`removable link fuse in connection with my device, details of which areshown in Figure et. The inner contacty member 2() of the fuse elementextends laterally trom the inner end ot an insulator tube 27, andpreferably` has a circular portion 28 enclosing one end ot said tube.Anend portion 27l ot the tube extends flush with the outer tace ot thedisl 28 excepting adjacent the contact member, for a purpose which u'illhereinafter be described. rlhe opposite, or outer end ot the tube 27 isdetachably connected to a cap member 29. preterzblv having' threadedengagement 30 in a collar 8l which is rotatably mounted at the innerface of the'cap member 29 and secured thereto by means ot a plate Thecollar 3lA is linurled shown in Figure l so that the tube may bereadiliv screwed and unscreived by hand, to assemble or disassemble thefuse element. A' slot 33 extends longitudinally from the outer end Y ofthe tube 27, toward the center thereof.

Y against by a spacing collar 40 which abuts the inner end of the disk32 when the fuse element is assembled. The opposite terminal for thefuse link comprises a terminal piece 41 having an enlarged flange 42,and a spindle 43 which extends thru the end disk 28 on the inner end ofthe fuse element. The

spindle 43 has a threaded portion V44 adja' cent the outer face of theend disk 28, and is provided with a nut 45 which clamps the terminalmember to said disk. rlhe fuse link 35 is detachably connected betweenthe link terminals 37 and 41 in any suitable manner, as for instance bybolts 56, 56.

The end of the spindle is adapted to t in a recessed bushing 46, formedinthe plug 4, but insulated therefromV by insulating bushing 47. Y

The outer end of the fuse element comprises the plug 29 having anannular body portion 49 adapted to fit tiglitly in the neck 50 of thecasing, and has a longbearing surface therein, so as to provide anexplosionproof joint, in which any flame from an arc, or an explosioncaused thereby, within the casing, cannot reach the outer air. The fuseelement 2 is provided with a handle 51, and is adapted to be locked inthe casing by means of a segmental flange 52 which is adapted to engagea corresponding lip 53 on the casing.

The operation of my device is as follows: The fuse element 2 is insertedin the casing with the Contact members 19 and 2O Vin their inverted, lordownward position, so as to register with the insulating tube 21 and thedownwardly extending portion 26 thereof, hereinbefore described. 1Whenthe fuse element,` is inserted to its farthest limit, the pin 43 seatsin the recess 46. The entire fuse element is then turned a half turn bymeans of the handle 51 so that the locking flange 52 on the fuse elementengages with the lip 53 to lock the fuse element firmly in place, asshown in Figure 1. As the fuse element is thus rotated, the contactmembers 19 and 29 are also removed from the inverted, or downwardposition. Two segmental slots 54 and 55 (shown in Figure 5) areprovidedV in the insulating tube 21, with which the contact members 19and 2O are adapted to register,` so that they may be turned from theirin verted, or downward position to a second position indicated in Figure1, where they engage with the contact shoes 17 and 18, respectively. Inthis position, therefore, the fuse element is locked in the casing andthe circuit thru the fuse is closed. It will now be clear that in orderto unlock the fuse element and casing, it is necessary to vreverse theabove described action, by rotating the fuse element so as to move thecontact inembers 19 and 2O out of engagement with Vtheir respectivecontact shoes 17 and 18, before the locking flange 52 can be unlocked,`and the fuse element withdrawn from the casing.

prefer to make the slot 54 and contact member 19 somewhat shorter thanthe'contact member 20, so that the latter cannot be accidently engagedwith the contact shoe 17. Otherwise, if it were possible to insert thefuse element part way into the casing, and then rotate it to contact themember 20 and shoe 17, a short-oircuiU might be formed thru the fuse andcontact member 19 to the casing 3.V The possibility of such ashort-circuit is eliminated, however, by constructing the shoes andslots of dierent lengths, as described.

l provide another safety feature in the construction of the inner end ofthe fuse element, in which the insulation 27a extends flush with the endportion 28 of the contact member 20, as already described.l I Yhavefound that it is possible to insert the fuse element at such an anglethat Ythe forward edge 27au of the fuse element Vmay extend thru theslot 54 and engage with the contact shoe 17. As this forward edge 27a isinsulated however, the possibility of shortcircuit 'from this cause iseliminated.l

A further feature of my invention is a construction which makes itpractically impossible for a careless operator to insert a substitutefor the fuse element'so as to close the circuit within the casing whilethe casing is unlocked. It is well known to those familiar with theoperation of safety devices of this character, that in spite of allwarnings as to the danger of overloading a circuit, and of explosionscaused by open fuse contacts, yet

a large proportion of operators will ignore all provisions for their ownwelfare by attempting to contrivev some method of defeating the purposeof the safety'device.` One of the common practices is to connect theordinary fuse terminals with fuse w're, and in fact Common wire, andmany other articles, are used for this purpose. lt will be seen,however, that with my improved construction, it is practicallyimpossible to reach the Contact shoes 17 and 1S for the purpose ofconnecting these ter ninals with any substitute for the fuse element inthe manner above suggested. lVhile it may be possible to insert fusewire or other substitute Yfor Vthe fuse link 35, yet when this is done,theentire ico lao

fuse element 2 must be inserted and locked before proper contact ot thefuse device can be made.

Having described my invention What I claim as new and desire to cover byLetters Patent, is:

l. In a device ot the class described, a casing, a removable fuseelement having a portion thereof adapted to form a closure ttor saidcasing, electrical contacts tor said Vfuse element Within said casing,contact members associated with said fuse element adapted to engage saidcontacts, and means independent ot' said contacts tor locking saidclosure in all positions of engagement between said contacts and contactmembers.

2. In a device ot the class described'.v a crising, a removable inseelement having a porti-on thereoft adapted to form a closure tor saidcasing, electrical contacts Within `said casing, contact members on saidfuse element adapted to engage the tirst named contacts, and meansindependent ot said contacts permitting insertion and removal ot said'fuse element only when said inse contact members are ont of engagementwith said contacts.

3. In a device of the class described, a cylindrical casing, a rotatablefuse element having an annular portion thereof adapted to torni aclosure tor said casing, electrical contacts tor said fuse element-Within said casing, mea-ns pern'iitting longitudinal movement of said'fuse element within said casing When said fuse contacts are out otIlongitudinal alignment with said casing contacts, and means permittingrotation ot said 't'nse element in said casing only when said annularportion is in fully closed position in said casing.

4. In a device ot the class described, a casing, a removable fuseelement having a portion thereof adapted to torni a closure tor saidcasing, a pair of contacts tor said fuse element in said casing, contactmembers on said fuse element, means permitting insertion and removal otsaid fuse element in one position with said fuse contact members removedtrom said casing contacts; means attording movement ot said t'nseelement in a second position With .said fuse contact members inengagement with said casing contacts, and means operable to lock saidclosure against longitudinal movement, in a position intermediate thetivo tirst mentioned positions of said fuse element.

5. In a device ot the class described, a casing, a rotatable fuseelement having an annular portion thereof adapted to form a closure forsaid casing, and having a pair orn laterally extending contact members.a pair of contacts in said casing for said inse contact members, saidcasing having a passageway affording entrance ot the fuse element in anaxial direction with the respective fuse and casing contacts maintainedat a distance t'rom each other, and means whereby the fuse element maybe rotated to engage the resprctive fuse and casing contacts only whensaid tese element is in closed position in said casing.

6. In a device of the class described, casing, a rotatable fuse elementadapted to be inserted in said casing to form a closure therefor, saidfuse element having a pair ot' laterally extending contact members and alock, contacts in said casing 'for said tnse Contact members, saidcasing having a passageway attordine entrance ot the frise element in anaxial direction with the respective tnse and casing contacts removed-trom each other, and means independent ot said contacts whereby thefuse element may be rotated to locl said tnse element against. axialmovement, and to engage the respective inse and casing contacts, saidfuse elementbeing iocked at all times that said t'nse and casingcontacts are engaged.

7. In a device ot the class desciibed, a casing, a fuse element havingan end portion thereof adapted to form a closure tor said casing andprovided with laterally extending contact members, electrical contactsin said casing, insulating means in said casing having a passagewayatiording entrance or' said fuse element with said t'nse contact membersmaintained out ot' registering position with said casing contacts, saidinsulating means also pei itting rotation ot said 't'nse contacts intoand ont ol engagement with said casing contacts When said casing isfully ciosed by said fase element. I

8. In a device ot the class described, a casing, a fuser element havingan end portion thereot' adapted to torni a closure tor said casing andprovided with laterally extending contact members, electrical contactsin said casing, insulating means in said casinghaving a passagewayaitording entrance of said 'inse element with said fuse contact membersmaintained out ot' registering position with said casing contacts, saidinsulating means also permitting rotation ot said 'fuse contacts intoand out ot engagement with the casingcontacts when said casing is closedby said end portion ot the vtuse element, and means independent ot saidcontacts for locling said fuse element against end\vise movement in saidcasing when the respective fuse and casing contacts are engaged witheach other.

9. In a device ot the class described, a casing having'electricalcontacts therein, a fuse element having longitudinally spaced,

members, insnlaterally extending contact lating means in said casinghaving a longitudinal passage permitting endivise entrance of said tnseelement .vhen the fuse contacts are out ot registering position withrespect 4casing having *electricalY contacts therein, a

t'use element having laterally7 extending contact members, insulatingmeans in said casing having a lonofitudinal Vpassage permit- 'tingendivise entrance of said fuse element when the fuse contacts are ont o'registering position with respect to said casing contacts,

saidinsulating means also having a pair of Y, v

casing, a removable fuse element comprising slots aiording rotation ofsaid contacts into and out o't` engagement with the casing con- YtactsandV O'uidinc means coactino' between n a: n ,l :a 1

the inner end ot. said inse element and tne.

casing. y

lL'ln a device ot the class described, a casing, a pair of electricalcontacts in said casing, spring devices securing said electricalcontacts to the casing, a fuse element having laterally extendingcontact members, insulating means in said casing'liaving a passagepermitting entrance of said fuse element when the fuse contacts aie ontot` registering position With respect to said casing contacts,

and means affording rotation of said fuseV contacts into and out ofengagement with the casing contacts. 1

12. ln a device of the class described, a

casing, a pair ot electrical contacts in saidV casing, spring devicessecuring said electrical contacts to the casing, conductor piecesassociated With said spring devices, Va fuse ele ment having laterallyextending contact members, insulating means in said casing having alongitudinalV passage affording endWise entrance ot said t'iise elementwhen the fuse contacts are out of registering position with respect tosaid casing contacts,

i3. in a device of the class described, a

casino', a removable `fuse element comprising b I r an annular endportion adapted to torni a closure :tor said casing, and a detachable,body portion having an insulating cover, a

pair ot' laterally disposedcontact member extending tlierethru, and afusible piece connecting said Contact members, said contact membersbeing adapted to engage ivith contact members in said casingivhen thefuse element is in closed position;` A f 1min a device of the classdescribed, a

an annular end portion adapted to forma closure tor said casing, and adetachable body portion extending axially from said end portion havinganinsulating cover, a j

`Vpair oi laterally disposed Contact members extending tliei'ethru, anda fusible piece connecting said Contact, said contact members beingadapted to engage With contact ineinbers in said casing When the tuseelement Y is in closed position.

l5. ln a device ot the class described, a casing, a removable fuseelement'coniprising an annular end portion adapted to form a closure torsaid casing, and a detachable body'portion having an insulating cover, apair of laterally-disposed contact members extending tlierethru, afusible piece connecting said contactinenibers, said contactmembersbeing adaptedto engage With Ycontact members in said casing When thefuse element is in closed position, and guiding means coacting betweenthe inner end ot said fuse element and said casing. Y

Signed at Chicago, Illinois, this 22nd day ot June, A. D., 1920. Y

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